52 research outputs found

    Resilient Network Coding in the Presence of Byzantine Adversaries

    Get PDF
    Network coding substantially increases network throughput. But since it involves mixing of information inside the network, a single corrupted packet generated by a malicious node can end up contaminating all the information reaching a destination, preventing decoding. This paper introduces distributed polynomial-time rate-optimal network codes that work in the presence of Byzantine nodes. We present algorithms that target adversaries with different attacking capabilities. When the adversary can eavesdrop on all links and jam zO links, our first algorithm achieves a rate of C - 2zO, where C is the network capacity. In contrast, when the adversary has limited eavesdropping capabilities, we provide algorithms that achieve the higher rate of C - zO. Our algorithms attain the optimal rate given the strength of the adversary. They are information-theoretically secure. They operate in a distributed manner, assume no knowledge of the topology, and can be designed and implemented in polynomial time. Furthermore, only the source and destination need to be modified; nonmalicious nodes inside the network are oblivious to the presence of adversaries and implement a classical distributed network code. Finally, our algorithms work over wired and wireless networks

    On Counteracting Byzantine Attacks in Network Coded Peer-to-Peer Networks

    Get PDF
    Random linear network coding can be used in peer-to-peer networks to increase the efficiency of content distribution and distributed storage. However, these systems are particularly susceptible to Byzantine attacks. We quantify the impact of Byzantine attacks on the coded system by evaluating the probability that a receiver node fails to correctly recover a file. We show that even for a small probability of attack, the system fails with overwhelming probability. We then propose a novel signature scheme that allows packet-level Byzantine detection. This scheme allows one-hop containment of the contamination, and saves bandwidth by allowing nodes to detect and drop the contaminated packets. We compare the net cost of our signature scheme with various other Byzantine schemes, and show that when the probability of Byzantine attacks is high, our scheme is the most bandwidth efficient.Comment: 26 pages, 9 figures, Submitted to IEEE Journal on Selected Areas in Communications (JSAC) "Mission Critical Networking

    Characterization of Band Codes for Pollution-Resilient Peer-to-Peer Video Streaming

    Get PDF
    We provide a comprehensive characterization of band codes (BC) as a resilient-by-design solution to pollution attacks in network coding (NC)-based peer-to-peer live video streaming. Consider one malicious node injecting bogus coded packets into the network: the recombinations at the nodes generate an avalanche of novel coded bogus packets. Therefore, the malicious node can cripple the communication by injecting into the network only a handful of polluted packets. Pollution attacks are typically addressed by identifying and isolating the malicious nodes from the network. Pollution detection is, however, not straightforward in NC as the nodes exchange coded packets. Similarly, malicious nodes identification is complicated by the ambiguity between malicious nodes and nodes that have involuntarily relayed polluted packets. This paper addresses pollution attacks through a radically different approach which relies on BCs. BCs are a family of rateless codes originally designed for controlling the NC decoding complexity in mobile applications. Here, we exploit BCs for the totally different purpose of recombining the packets at the nodes so to avoid that the pollution propagates by adaptively adjusting the coding parameters. Our streaming experiments show that BCs curb the propagation of the pollution and restore the quality of the distributed video stream

    Complexity of Multi-Value Byzantine Agreement

    Full text link
    In this paper, we consider the problem of maximizing the throughput of Byzantine agreement, given that the sum capacity of all links in between nodes in the system is finite. We have proposed a highly efficient Byzantine agreement algorithm on values of length l>1 bits. This algorithm uses error detecting network codes to ensure that fault-free nodes will never disagree, and routing scheme that is adaptive to the result of error detection. Our algorithm has a bit complexity of n(n-1)l/(n-t), which leads to a linear cost (O(n)) per bit agreed upon, and overcomes the quadratic lower bound (Omega(n^2)) in the literature. Such linear per bit complexity has only been achieved in the literature by allowing a positive probability of error. Our algorithm achieves the linear per bit complexity while guaranteeing agreement is achieved correctly even in the worst case. We also conjecture that our algorithm can be used to achieve agreement throughput arbitrarily close to the agreement capacity of a network, when the sum capacity is given
    • 

    corecore